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NCT Number: NCT06425562

The Potential Added Value of Impulse Oscillometry in Asthma Monitoring

The goal of this longitudinal observational study is to learn if impulse oscillometry (IOS) has an added value in asthma monitoring in adult asthma patients who are prescribed a change in asthma maintenance therapy. The main questions it aims to answer are:

* Is there a difference in the change in IOS parameters and FEV1 respectively, stratified according to change in asthma control test? * Is there a difference in the change in IOS parameters and FEV1 respectively, stratified according to change in other questionnaire such as the asthma control questionnaire and the asthma quality of life questionnaire. * Are the proposed minimal clinically important differences (MCIDs) valid for short follow-up periods (3 - 6 months)?

Participants will undergo lung function testing (full lung function, multiple breath nitrogen washout, impulse oscillometry) and questionnaires (asthma control test, asthma control questionnaire, asthma quality of life questionnaire), once during the baseline visit and once during the follow-up visit three to six months later.

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Key information

Conditions

Asthma Bronchial Diseases Hypersensitivity Hypersensitivity, Immediate Immune System Diseases Lung Diseases Lung Diseases, Obstructive Respiratory Hypersensitivity Respiratory Tract Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Universitair Ziekenhuis Brussel

Brussels, 1090, Belgium

Location status: Recruiting

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adult asthma patients with a scheduled consultation at the outpatient hospital to whom a step-up or step-down of their pharmacological asthma treatment is prescribed

Exclusion criteria

  • Unstable asthma (defined as need for oral corticosteroids or (respiratory) antibiotic course in the 4 weeks before inclusion or any major medical issue in the 4 weeks before inclusion)

Treatment and study plan

Full lung function

Other

This includes spirometry, body plethysmography and single breath gas transfer test. These are all non-invasive physiological measurements / lung function tests. Measures flow volumes, lung volumes and gas transfer respectively.

Multiple breath nitrogen washout

Other

Non-invasive physiological measurement / lung function test. 100% oxygen is inhaled and the nitrogen concentration in the lungs is measured. This test gives information on the ventilation distribution in the lungs.

Impulse oscillometry

Other

Non-invasive physiological measurement / lung function test. This technique superimposes sound waves on tidal breathing. The patient can breathe normally trough the device, no forced respiratory maneuvers are required. It gives information on the reactance and resistance of the lung.

Primary outcomes

  1. Change in frequency dependance of resistance (FDR) stratified according to change in asthma control test (ACT)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Frequency dependance of resistance (FDR) is an impulse oscillometry parameter. FDR is expressed in kPa/(L.s). A lower FDR indicates a clinically better outcome. The ACT is a questionnaire which consists of 5 questions, each evaluated on a 5-point Likert-Scale. Total score ranges between 5 and 25, where a lower score is clinically worse than a higher score.

  2. Change in area of reactance (AX) stratified according to change in asthma control test (ACT)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Area of reactance (AX) is an impulse oscillometry parameter. AX is expressed in kPa/L. A lower AX indicates a clinically better outcome. The ACT is a questionnaire which consists of 5 questions, each evaluated on a 5-point Likert-Scale. Total score ranges between 5 and 25, where a lower score is clinically worse than a higher score.

  3. Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma control test (ACT)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Spirometry parameter: forced expiratory volume in 1 second (FEV1). FEV1 is expressed in L. A higher FEV1 indicates a clinically better outcome. The ACT is a questionnaire which consists of 5 questions, each evaluated on a 5-point Likert-Scale. Total score ranges between 5 and 25, where a lower score is clinically worse than a higher score.

Secondary outcomes

  1. Change in frequency dependence of resistance (FDR) stratified according to change in asthma control questionnaire (ACQ-6)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Frequency dependance of resistance (FDR) is an impulse oscillometry parameter. FDR is expressed in kPa/(L.s). A lower FDR indicates a clinically better outcome. The ACQ-6 is a questionnaire which consists of 6 questions, each evaluated on a 7-point Likert-Scale. The total score score is divided by 6 yielding a mean score ranging from 0.0 to 6.0, where a lower score is clinically better than a higher score.

  2. Change in area of reactance (AX) stratified according to change in asthma control questionnaire (ACQ-6)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Area of reactance (AX) is an impulse oscillometry parameter. AX is expressed in kPa/L. A lower AX indicates a clinically better outcome. The ACQ-6 is a questionnaire which consists of 6 questions, each evaluated on a 7-point Likert-Scale. The total score score is divided by 6 yielding a mean score ranging from 0.0 to 6.0, where a lower score is clinically better than a higher score.

  3. Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma control questionnaire (ACQ-6)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Spirometry parameter: forced expiratory volume in 1 second (FEV1). FEV1 is expressed in L. A higher FEV1 indicates a clinically better outcome. The ACQ-6 is a questionnaire which consists of 6 questions, each evaluated on a 7-point Likert-Scale. The total score score is divided by 6 yielding a mean score ranging from 0.0 to 6.0, where a lower score is clinically better than a higher score.

  4. Change in frequency dependence of resistance (FDR) stratified according to change in asthma quality of life questionnaire (AQLQ)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Frequency dependance of resistance (FDR) is an impulse oscillometry parameter. FDR is expressed in kPa/(L.s). A lower FDR indicates a clinically better outcome. The AQLQ is a questionnaire which consists of 32 questions, each evaluated on a 7-point Likert-Scale. The total score is divided by 32 yielding a mean score ranging from 1.0 to 7.0, where a lower score is clinically worse than a higher score.

  5. Change in area of reactance (AX) stratified according to change in asthma quality of life questionnaire (AQLQ)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Area of reactance (AX) is an impulse oscillometry parameter. AX is expressed in kPa/L. A lower AX indicates a clinically better outcome.The AQLQ is a questionnaire which consists of 32 questions, each evaluated on a 7-point Likert-Scale. The total score is divided by 32 yielding a mean score ranging from 1.0 to 7.0, where a lower score is clinically worse than a higher score.

  6. Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma quality of life questionnaire (AQLQ)

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    Spirometry parameter: forced expiratory volume in 1 second (FEV1). FEV1 is expressed in L. A higher FEV1 indicates a clinically better outcome.The AQLQ is a questionnaire which consists of 32 questions, each evaluated on a 7-point Likert-Scale. The total score is divided by 32 yielding a mean score ranging from 1.0 to 7.0, where a lower score is clinically worse than a higher score.

  7. Change in frequency dependence of resistance (FDR) over the 3-6 months observation period compared to proposed minimal clinically important differences (MCIDs) (calculated for a one year interval) for FDR.

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    MCIDs over 1 year have been published for IOS parameters. For frequency dependence of resistance (FDR) the MCID is defined as a decline of FDR greater or equal to 0.06 kPa/(L.s). Change of FDR ≥ 0.06 kPa/(L.s) or not

  8. Change in area of reactance (AX) over the 3-6 months observation period compared to proposed minimal clinically important differences (MCIDs) (calculated for a one year interval) for AX.

    Time frame: Once at baseline and 3 - 6 months later during follow-up

    MCIDs over 1 year have been published for IOS parameters. For area of reactance (AX) the MCID is defined as a decline of AX greater or equal to 0.65 kPa/L. Change of AX ≥ 0.65 kPa/L or not

Study contacts

Contact information is provided by the study sponsor or research team.

Shane Hanon, Prof. Dr. MD.

CONTACT

[email protected]

02 477 6841

Sponsors and collaborators

Lead sponsor

Universitair Ziekenhuis Brussel

Other

Collaborators

  • Vrije Universiteit Brussel

Registry information

Acronym: AM-IOS

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
May 22, 2024
Registry last updated
Sep 15, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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